Multiple electrodes and connecting wires for neural and muscular stimulation and measurement device

ABSTRACT

A device to make multiple, simultaneous measurements of electrical activity on neural, muscular and other animal cells. The invention discloses multiple electrodes at fixed position on a supporting structure and multiple wires to connect the electrodes to one or more measuring devices. The electrodes are preferentially closed spaced, to allow for small spatial discrimination between measurement points. The electrodes and the wires are selected by binary addresses. The device is also capable of injecting electrical stimulation using electrodes not in use for measurements. An injected electrical stimulation at a first location may be created to measure the effect of a well-known event at another location or locations, near or far away.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is based on, and claims benefit of ProvisionalApplication Ser. Nos. 61/194,515, filed Sep. 29, 2008; and 61/198,029,filed Nov. 3, 2008.

FEDERALLY SPONSORED RESEARCH

Not Applicable

SEQUENCE LISTING OR PROGRAM

Not Applicable

BACKGROUND OF THE INVENTION Field of Invention

This invention relates to cellular electrical measurements in general,for animals, including humans, and neuron electrical measurements inparticular.

DEFINITION OF TERMS

To assert. In digital electronics it means to make a wire on or off, asneeded, or a set of wires to be in any combination on and off, asneeded. In this context “on” an “off” generally mean one of the twopossibilities of a binary representation, as on=5V, off=0V, on=magneticfield up, off=magnetic field down, on=light, off=dark, etc.

B/H/D after a number, or in subindex, stands for binary/hexadecimal(hex)/decimal number representation. For example: 1010B=0AH=10D

Bus. A set of wires grouped according to its function. For example, theaddress bus is the set of wires which carries the address value forsomething, the data bus is the set of wires which carries the data, ornumerical value for something.

Demultiplexer. A type of electronic switch with a single input and aplurality of outputs, also with a number of binary inputs capable ofcreating a binary address which can select which of the outputs will beconnected to the single input (cf. multiplexer). The device of ourinvention uses a demultiplexer capable of also latching the outputselection, that is, a demultiplexer that maintain the connection betweenthe single input and the selected output even after the address is outfrom its address port (it latches), or even if the address changes toanother value.

Integrated circuit. As used herein, the term “integrated circuit” refersto a small-scale, electronic device densely packaged with more than oneintegrated, electrical component. The components are manufactured on thesurface of semiconductor material. There are various scales ofintegrated circuits that are classified based on the number ofcomponents per surface area of the semiconductor material, includingsmall-scale integration (SSI), medium-scale integration (MSI),large-scale integration (LSI), very large-scale integration (VLSI),ultra large-scale integration (ULSI)

Latch. A term used in digital electronics meaning the capability to keepsome particular configuration, or output, or logic, or selection, evenafter the selecting source, etc., is no longer active, or even if theselecting source is changed to a different value. Another way to look atit is that a latched device has memory to keep a configuration wheninstructed to do so. A standard wall light switch is an example of alatch because it keeps the last state it was set by a human being,either on or off.

Measuring tip. The very tip of the measuring wire, sometimes referred aselectrode in current art, made of metal or some other electricallyconducting material. In current art devices the measuring tip isgenerally at the end of a thin, stiff wire, typically 100 micrometersdiameter, separated by 100 micrometers, or more, while in our inventionthe measuring tip is a metallic area as small as a few micrometers,typically 5 micrometers but can be less or more according to the need,separated by as little as 5 micrometers, at the surface of the device ofour invention. Current art is capable of manufacturing measuring tipsfor our invention that are less than one micrometer in diameter, and theshape is not necessarily circular.

Multiplexer (MUX) a type of electronic switch with a plurality of inputsand one single output, also with a number of binary inputs capable ofcreating a binary address which can select which of the inputs will beconnected to the single output. (cf. Demultiplex).

Neural sensor. As used herein, the term “neural sensor” means animplantable device for sensing neural signals. Examples of neuralsensors include microwire electrode arrays, optical sensors, microwires,magnetic field detectors, chemical sensors, and other suitable neuralsensors which are known to those of skill in the art upon considerationof the present disclosure.

Picafina. A supporting structure used by the main embodiment of ourinvention, generally similar to the devices used in Deep BrainStimulation but potentially with far more tips or electrodes than DBSdevices, which is strong enough to allow it to be inserted in the brainor other body structures, and which contains the necessary wires forconnecting the measuring tips and the address decoders with thecontrolling and measuring instruments. For use human animals, hedimension of a type I picafina is approximately the size of a widedrinking straw (5 mm.), its length being the necessary to reach thedesired depth in the body. For smaller animals (as a mouse), thepicafinas would be accordingly smaller, both in diameter and length,while for larger animals (as a whale or an elephant), the picafinaswould be accordingly larger.

SHORT INTRODUCTION TO THE ART

It is well established that the neuron signals are electricallypropagating signals. The roots of this fact can be traced at least tothe Italian Luigi Galvani as early as 1771 with his famous frog's legexperiment.

This neuronal (electrical) traffic travels in both directions, fromeither the brain or intermediate neurons to the muscles or other bodyparts, or from sensory organs (skin, taste buds, vision rods and cones,etc.) to either other intermediate neurons or the brain. Measuring thesesignals is of importance for at least two reasons: such measurements maygive us a clue of how the brain works; they may also help us to developelectrical actions on the nerves and on the brain to do things as tostop pain or to stop Parkinson's disease tremor or to stop epilepticseizures, etc. Accordingly, much effort has been put into devices tomeasure the neuronal electrical activity. Eric Kandel (Kandel (2000))gives a good overview of the current state of the art from the academicpoint-of-view, while Miguel Nicolelis (ed.) (Nicolelis (2008)) gives acurrent review of the electrodes measuring devices directly related tothe our invention here disclosed.

Accordingly, to measure the neuronal electrical activity, severalmeasuring electrodes, or probes, or measuring pads, or measuring tips,henceforth most often referred to as “measuring tips” or simply “tips”have been developed.

The single tips used in the early days of the art have given place tomultiple tips, and the sizes of said tips is much smaller in currentart. These multiple tips have a double objective. One is to makesimultaneous measurements, both to collect more data, as well as toinvestigate the correlation between the firing of different neurons. Asecond objective is associated with the widely known difficulty ofaccurately positioning said tips with its distal end at the precise areaof interest, at a precise position relative to any neuron, say, close toa synapse, or to a particular neuron. With multiple tips, one of them,by chance, may happen to be near one of the areas of interest, sosupporting devices with several tens, or even over one hundred tips havebeen introduced. Yet, in spite of the recognized need of betteradjustment of the measuring point, no real solution has been offered tothis known problem: how to have a very large number of reading positionson the area studied, for example a brain (or a spinal cord, or somenerve bundle going to or from a finger, etc.). A device with moremeasuring tips, capable of measuring more points, and also points thatare closer to each other is needed. Note also that the multi electrodearrays of current art cannot select a position a few micrometers near aparticular position, but only the other electrode at the end of anotherwire, that, because it is separated by a supporting structure, canhardly be less than 100 micrometers away. It follows that current artcan only make measurements at points which is too far for the smallsynapses that may measure just a few micrometers. The advantage, or evennecessity, of having a larger number of electrical tips to serve aselectrical measuring points is known in the community, yet, despite muchinterest and work devoted to it, no solution was ever proposed to thisknown problem. Indeed, given the picafina diameter limitations, there isan intrinsic limitation on the number of wires that can be carriedinside it, which in turn sets a limit on the number of possible tips onits surface—or so is accepted by current art. The small number of tips(electrical contacts) has been one of the recognized problems associatedwith the art, a problem which has never solved even though much efforthas been put to its solution. This is a problem that has been crying forsolution for a long time. This is the problem addressed and solved byour invention.

Our invention is a picafina with a much larger number of tips than thecurrent art devices, potentially of the order of many thousand tips.Besides disclosing a device with such a larger number of tips, ourinvention discloses a method to bring out the voltage values, withoutwhich the small diameter of said picafinas would not allow such largenumbers of tips to send out the measured values using dedicated wires,as dedicated wires to each tip would not fit inside current artpicafinas which have to be as small as possible in order to minimizetrauma to the animal.

DISCUSSION OF PRIOR ART

The measuring tips or electrodes, as it is said within the neurologycommunity, or neuron measuring electrodes or tips, to be more precise,are in prior art made of small electrically conductive tips, physicallyattached to some supporting structure, which is usually small to beaccommodated inside the body of a living animal (including humans). Theycan be viewed as neural sensors. This electrical measuring tip, orneural sensor, is connected as needed to some usually external measuringinstrument (usually a voltmeter) after being amplified, thisamplification often occurring still inside the animal at the probelocation. The electric potential at the neuron site is of the order ofmicrovolts to millivolts. Often the electrodes, or probe, or tip, orpad, are held by equipment to help the researcher or neurosurgeon tomove the tip with micrometer precision, which is needed to position itin close vicinity to a neuron (Nicolelis (2008), ch 1, pgs 12-20)

The measuring tip has to be such that it can be placed substantiallyclose to the intended neuron, usually of the order of a few micrometersor even a fraction of a micrometer distance. The measuring tip itselfhas to be of a size comparable with the physical size of the system thatis producing the signals it is measuring, that is, of a size comparablewith the size of a neuron, or else it will make contact with othernearby systems, measuring averages from several neurons at the sametime. This means that the measuring tip has to have a size on the orderof one to a few tens micrometers in diameter, if it is to measure anindividual neuron. There are probes intended to measure a group ofneurons, and these can be larger.

Examples of multi electrode arrays in current use can be seen at G.Lehew and M. A. L. Nicolelis “State-of-the-Art Microwire Array Designfor Chronic Neural Recordings” in Nicolelis (2008) pg. 1, where thereare descriptions and photos of multi electrode arrays from 8 up to 128electrodes or tips. The problem with these electrodes is that they areon individual, separated supporting wires, one wire for each tip, whichincrease the trauma on the animal, and prevent the electrodes from beingless than 100 micrometers separation from each other. Scott J.Cruikshank and Barry W. Connors (Cruikshank (2008)) and James F. A.Poulet and Carl C. H. Petersen (Poulet (2008)) also discuss the needs,problems and current state of the art of multi electrodes measuringdevices.

Some of the current art devices are the electrode manufactured by AlphaOmega Engineering (http://www.alphaomega-eng.com/microelectrods/sma.asp)(Alpha Omega Engineering/PO Box 810/Nazareth Illit 17105/Israel/Tel972-4-656-3327/Fax 972-4-657-4075/info@alphaomega-eng.com)

Many probes have several measuring tips, which allow concurrentmeasurements on several neurons. The multiplicity of tips also serves toadjust the exact point of measurement, because it is known to bedifficult for the researcher (in a laboratory animal) or for theneurosurgeon (on a human patient) to position said measuring tip next toa particular neuron of such small dimensions. Ultimate measurementlocation is adjusted by selecting one or other (or several) of said tipsor contacts. Tip selection is then made after insertion of the probe inthe general area from which measurements are to be made, as theresearcher, or the neurosurgeon, switch the measuring equipment from onetip to the next until, after having flipped through many tips thatproduce no signal or poor signal, he/she finds a tip that produces agood signal. There are also multi tips devices which allow each tip tobe moved independently, usually forward and backwards only. Ourinvention offers an improvement on this change from one measuring tip toanother, making it easier and more efficient. Our invention also allowsthe investigator or the neurosurgeon to make concurrent measurements onneurons closer together than previous art multi tip probes which have tobe separated by the minimum distance of their supporting wires, which isof the order of 100 micrometers or more.

Irazoqui-Pastor (Irazoqui-Pastor (2008)) discloses an implantable devicewith multiple reading tips and a MUX (multiplexer), but he does notdisclose a method and a means to have measuring tips that are very smalland in very close proximity to each other (densely packed), in such away as to cover a large area with selectable tips. In particularIrazoqui-Pastor does not disclose a system capable of combining themeasuring tips together to make measuring areas of variable sizes,adjustable to the neuron size and location. And above all,Irazoqui-Pastor implicitly discloses an invention in which a largenumber of signal wires have to be brought to the MUX, a situation thatforestalls a very large number of measuring tips in a small device. Nordid Irazoqui-Pastor disclosed a method to select a particular measuringtip then to keep it selected and to have a few selected together.Indeed, Irazoqui-Pastor disclosed the use of a MUX in the conventionalway, which is in situations where space is not a problem. Because ofthese reasons, the invention disclosed by Irazoqui-Pastor fails to teacha method to allow a very large number of tips to be used, say, hundredsor thousands of tips, and accordingly, Irazoqui-Pastor does not mentionthe possibility of thousands of measuring tips.

Jenkins et al. (Jenkins (2006)) discloses a multiple tip system both foracquiring electrical signals and applying stimulation as well, but hisinvention is limited in that as disclosed, the number of measuring (orstimulating) tips is limited, like all previous art electrodes, by thenumber of wires that can fit on the elongated body of the device.Superficially, Jenkins teachings is similar to mine, but without a verylarge number of individually addressable tips, the researcher cannotadjust precisely the location of measurement to be near one singleneuron, and in this is the fundamental difference between his inventionand mine. The need for a large number of contact tips has beenrecognized for a long time, and similar devices with multiple rings havebeen in use for Deep Brain Stimulation (DBS) (Medtronics (n/d)), but theconstraint on the number of wires has kept the devices from advancing.Moreover, Jenkins failed to disclose the possibility of using thesemiconductor manufacturing and printed circuit boards manufacturingtechniques to achieve the smallest sized tips, what limits his tips torelatively large sizes.

Another example of modern prior-art devices is Donoghue et al. (Donoghue(2007)). His invention discloses a multi tip device, with each tip atthe end of a small needle. Using this construction, the minimumseparation of the tips is twice the size (diameter) of the supportingneedle. Since the supporting needle can hardly be smaller than 50micrometers, else it breaks, the distance between two reading electrodesis 100 micrometers minimum. Since 100 micrometers is much more than thesize of a synapse in a typical brain neuron, it follows that thisstructure cannot adjust the measurement position with accuracies of theorder of a fraction of the size of a neuron, as our invention can, andas it is needed.

Another examples of use of measuring devices are heart, muscle, paincarrying nerves, spinal cord etc.

OBJECTS AND ADVANTAGES

Accordingly, several objects and advantages of our invention are

1. The possibility of controlling a much larger number of electricaltips, or neural sensors, for measurements of electrical activity from amultiplicity of points, many more than in prior art, adding flexibilityto the user

2. The possibility of controlling which said tips are on or off withoutusing a dedicated wire to each said tips, because there is not enoughroom in the body of the supporting structure for many wires,

3. The possibility of housing and running through the picafina's limitedspace a smaller number of controlling wires from O&A (Objects andAdvantages) #1, when a larger number of wires would be impossible to fit

4. The possibility of making measurements on brain neurons in insects,human and non-human animals. These deep brain locations control limbmotion and may be involved in Parkinson's disease, epilepsy or otherdysfunctions, so measurements may be necessary for diagnosis, while inresearch animals such places may be accessed for measurements forresearch purposes. FIG. 1 shows a perspective view of a basic version ofour invention for a particular main embodiment used for deep brainmeasurements. For deep brain measurements the objective is to makemeasurements from parts of the brain that are deep inside the skull, asthe thalamus.

Other objects and advantages are:

Thus one of the problems that this invention solves is how to make avery large number of electrical measuring tips on the surface of saidpicafina, in such a way that some of said measuring tips can beconnected to an electrical measuring device, as a voltmeter, one at atime, or a few at a time, but using far less wires than the number ofmeasuring tips.

Summing up, one of the objectives of this invention is to provide aphysical means and a method to allow for a larger number of measuringtips than current art permit to have

Further objects and advantages of our invention will become apparentfrom a consideration of the drawings and ensuing description.

SUMMARY

The invention is a method and a means to provide a large number ofelectrical tips from which to make measurements of the electricpotential (voltage) at neurons and other cells of mammal animals,including humans, also of fishes, birds and even insects (Wilson(2004)).

Said measuring electrode tips at the end of said picafina, or electricalcontacts at the distal end of the support, can have dimension as smallas on the order of a fraction of or a few micrometers, and the distancebetween them can be similar in size too. If the picafina were insertedin the exactly desired position, that is, next to a neuron, then onesingle measuring tip would be all that would be needed. Unfortunately itis not possible for the surgeon to so precisely position the distal endof the picafina next to a neuron that he cannot see, in such a way thatthe measuring tip is next to a desired neuron. Moreover, the desiredneuron is hard to locate, among other reasons due to the variety ofinner brain (or any other tissue) structure from patient to patient.Indeed, though the relative position of all brain structures is the sameon all patients, their physical size, and therefore their absoluteposition with respect to any fiducial mark is not the same. This is truefor internal as well as external features: all humans have their nosesabove their mouths but their absolute distances measured from, say, theforehead, vary from individual to individual. In reality the distancesare guaranteed to be different from individual to individual. It followsthat the electrode positioning is less accurate than desirable. It isthis intrinsic positional inaccuracy that is solved with our invention,which is a method and a means to handle extremely large numbers ofmeasuring tips, which are positioned closer to each other than currentart. With this large number of available measuring tips, the researcheror the neurologist can select the one that happens, by chance, to be atthe desired location. All the electrodes in the main embodiment of thepicafina of our invention make use instead of the same wire through adedicated digital switch that can be turned on and off with a digitaladdressing system to select which measuring tip will be connected tosaid signal carrying wire. It is also possible to have a few wires tocarry measurements out, in which case more than one measurement can bemade simultaneously, and alternate embodiments of our invention disclosethe possibility of multiple concurrent measurements. Such alternativeembodiments are fitted with one address bus to select which measuringtip to use and a separate bus (a signal wire bus) to select which wireto use with the selected measuring tip. In one case or another, thereare fewer wires out than there are measuring tips.

It would be from difficult to impossible to dedicate a wire to carry thevoltage signal from each point-like, small electrode on the picafina,the difficulty increasing with larger number of measuring electrodes.The dilemma is that there is a need for a very large number of measuringtips, while there is no space for that many wires to carry out themeasured voltage. The need for a large number of tips, or points fromwhere to measure the voltage, exists because it is impossible toposition the device with any accuracy next to a neuron that is unseenbecause the animal is alive (its body is working!), so that finalplacement adjustment is made by trial and error trying one (or a group)of tips until the best one(s) is (are) discovered. Sometimes severaltips are used for simultaneous measurements too, useful to compare onewith the other.

The need for such a large number of tips has been recognized for a longtime (see Nicolelis (2008), preface Pgs. xiii to xv), and because thetips are much smaller than the wires connecting them to the outsidemeasuring instruments, the limiting factor is the wire size. So, despitemany attempts to make a large number of tips, never a solution was foundof how to accommodate the large number of wires in the small spaceavailable, one wire for each tip, even if a common ground is used. Norwas ever a solution found for the need to keep the tips very close toeach other. Current art offers tips that are approximately 250micrometers apart, sometimes 100 micrometers separation, less than whatresearchers and neurosurgeons want. The first embodiment of ourinvention solves one part of this problem with the use of one singlewire to carry the signal, which can then be connected to any of thelarge number of measuring tips after the picafina is in place. A secondalternate embodiment of our invention goes further, with the option of amultiplicity of wires (2 sup 4=16, 2 sup 6=64, or more wires) that canbe individually connected to as many measuring tips, offering thepossibility of parallel measurements. Indeed, one of the obstaclesencountered by current art (see Nicolelis (1998), Nicolelis (2008)) isthat it becomes difficult to insert more than a few dozen or perhaps 100wires in the brain or spinal column because of the potential damage totissues, with the potential of eventually killing the animal. Ourinvention solves this problem of having a large number of measuring tipseach of small size, while keeping a small number of connecting wires.The small size of the tips in turn allow for more precise choice of thelocation where the measurement is made.

DRAWINGS

FIG. 1 shows an oblique view of a possible embodiment the picafina ofour invention

FIG. 2 shows the end of the picafina also with three rows of electrodesequally space as in FIG. 1 but with electrodes of a square shape.

FIG. 3 shows the end of the picafina also with three rows of electrodesequally spaced as in FIG. 1 but with elongated electrodes along thecircumference direction.

FIGS. 4 a, and 4 b, show another version of the picafina of ourinvention with a larger number of smaller electrodes for a largerelectrode density as compared with FIGS. 1 through 3. FIGS. 4 a, and 4b, depict a perspective view, and a proximal end view of this version.Cf with FIG. 10, which does not have pads on the concave tip of thedistal end of the picafina. These are examples of modifications to adaptto particular needs, all within the scope of our invention.

FIGS. 5 a and 5 b show variations on current art of picafina that can beimplemented with existing technologies that allow a small number ofelectrical contacts.

FIGS. 6 a and 6 b show an alternate profile for the picafina.

FIG. 7 a and FIG. 7 b show a block diagram of a possible electricalconnection for the picafina of our invention laid on a picafina crosssection perpendicular to its long, or z-dimension. Note that FIG. 8 issimilar with the added multiplicity of measuring wires disclosed in thesecond embodiment. To avoid over-complication, only one of the measuringtips and its connections is shown in the cross section, similar circuitsexisting to serve each of the tips 110 at the surface of the device.Also to avoid over-complication, only three address lines are shown;typical devices use 8 and more address lines, to address 256 (2 power 8)measuring tips 110 and more. The ground wire can be connected to one ormore of the tips 110, with similar circuits.

FIG. 8 a and FIG. 8 b show, in addition to the elements shown in FIG. 7,the added multiple measuring wires disclosed in a second embodiment. Thephysical lay-out of some of the similar electronic circuits that connecteach of the tips on the surface of the picafina to the measurement wirethat run inside the picafina along the z-direction. The tips shown areall at a particular fixed distance from either end of said picafina, oraround a circular path on said picafina, as if along a ring on saidpicafina. Several such circuits are stacked along the longer dimensionof the picafina (different z-coordinate), each serving to connect one ofthe tips that comprise that particular “ring” to the wire connecting tothe measuring instruments.

FIGS. 9 a and 9 b show two possible address decoders, (a) set to decodefor the address 1 decimal=1 Hexadecimal=0000 0001 Binary, (b) set todecode for the address 12 Decimal=C Hexadecimal=0000 1100 Binary. Eachaddress decoder has a different configuration of inverters, eachdifferent decoder associated with a measuring tip.

FIG. 10 shows a main embodiment of our invention with 12 electric tipsor pads around the circumference of the picafina (or a “ring” of tips),16 such “rings” and no electric tip on the concave extremity of thepicafina.

FIG. 11 shows a window environment with the drop-down menus forprogramming the Doctor's Programming Unit (DPU)

FIG. 12 shows a picafina with redundant wires at its proximal end.

DRAWINGS List of Reference Numerals

-   -   h_1=length of the distal part of the picafina, which is        sometimes devoid of electrical tips.    -   h_2=length of the middle part of the picafina, which is        populated with electrical tips.    -   h_3=length of the proximal part of the picafina, which is devoid        of electrical tips.    -   100=body of picafina of our invention.    -   110_xx_yy=tips/electrical contacts on the surface of body 100.        These are the actual neural sensors. xx and yy are indexes for        the tips; for example, xx could indicate a set of tips at the        same distance from the extremities (or a z-coordinate on a        cylindrical coordinate system), and yy could indicate an angular        coordinate (or a theta coordinate on a cylindrical coordinate        system). In the main embodiment xx takes any value from 01 to        16, while yy takes any value from 01 to 12. As is appreciated by        anyone familiar with the art, 12 and 16 are exemplary numbers        only, the same principle being valid for any quantity of tips.        In particular, our invention allows for many thousands of tips,        when the numbers could typically be: radius of tip=0.1 mm (100        micrometers), center-to-center distance between tips=0.2 mm (200        micrometers), 75 tips on the 2.5 mm diameter picafina of FIG.        10, 20 rings equally spaced at 0.2 mm from each other along the        z-dimension, on a total 4 mm length along the picafina populated        with 1,500 measuring tips. These are possible typical values        which do not limit our invention, as any person skilled in the        art will notice that such dimensions must be adjusted to each        particular application.    -   810_xx_yy=on/off electronic switch that connect each electrical        tip to the common measuring wire(s), also indicated as 810-x,        when referring to any of the possible switches.    -   811_xx_yy=on/off electronic switch that connects the signal        carrying wires. Can be part of a demultiplexer.    -   820_xx_yy=timer or pulse stretcher, where xx indicates which        “ring” or z-distance, while yy indicates which of the 12 pads in        each “ring” in FIG. 10.    -   830_xx_yy=address decoders for the measuring tips    -   831_xx_yy=demultiplexers for signal wires that carry the signal        from the measuring tips to the proximal end of the picafina. It        could also be address decoders to make this connection or any        other similar device.    -   1810 b=summing amplifier between the measuring tip 110 and the        electronic switch 810    -   200=address lines, or address bus    -   200tip=address lines used for the tip selection    -   200wire=address lines used for the signal wire selection    -   200prox=proximal side of digital address lines    -   210=electrical power wire.    -   210prox=proximal side of electrical power wire.    -   211=measurement (signal) wire    -   212=ground wire

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Description of OurInvention—Short, Electrical Engineering Version of Preferred Embodiment

We start with a succinct description suitable for electrical engineers,then follow with a detailed description for wider audiences. The problemthat our invention address is to make electric voltage (or current)measurements from internal body parts, as brain, spinal cord, heart ormuscles, which may even be not visually accessible. The target point ofmeasurement may also be difficult to locate precisely. To get around thedifficulty, or even impossibility, of precisely positioning a relativelysmall measuring probe next to a desirable, target neuron (for example),that the researcher or the neurosurgeon may not even able to see, ourinvention discloses a device, here called picafina, which is larger thanthe hard to locate point of interest. This picafina is thenapproximately placed in the target location. Such picafina is coveredwith a multitude of surface electrodes or tips, here called measuringtips, or simply tips, which are of such a size and placement as to coverall the potentially desired points—and more. Given the small size of thetips, as indicated in FIG. 10, and their close proximity to each other,spanning all the potential area of interest, some of the tips 110_xx_yyshould be close enough to some of the several or single potential pointsof interest. After a surgeon inserts such device, the picafina, eitherthe surgeon or a nurse or a technician can select which tips to use,typically by observing the measurements from each tip, one at a time.

Using common techniques of semiconductor and printed circuit boardmanufacture, it is relatively easy to make a large number (manythousands and more) of relatively small tips (sizes of the order ofmicrometer or even sub-micrometer) on the surface of the picafina, atits distal extremity, as illustrated in FIG. 10, with the objective oflater selecting one or another tip, to precisely control the place whereto collect the data, but it turns out that there is a stringent limit onthe number of wires that may be pulled inside the picafina to connectthese tips to the measuring equipment, because these wires have to gothrough the limited space available in the body. So, in animals,including human beings, the limited space available for the larger wireslimits the number of smaller tips possible to use—each tip needs a wireconnecting it to the measuring device. For research with small animals,such as mice, or even insects (Wilson (2004)), current technology canput a many dozen and rarely a few hundreds wires at maximum in thelimited available space, therefore a few dozen (or hundreds) tips onlycan be used (Gregoire Courtine, private communication). To make use ofmore tips than wires to connect them to an external instrument, the mainembodiment of this invention discloses the use of a digital addressingsystem, which connects one tip at a time to the measuring device. Thetip is chosen with the objective of measuring at a particular location,which can be later changed. These locations can be in close proximity,closer than individual tips in prior art could be individuallypositioned. Jumping from a particular tip to a nearby one, theresearcher or neurologist has the possibility of selecting measurementpositions with as much accuracy as the tips are apart from each other.Moreover, there is a need to keep more than one tip connected to themeasuring device, so this invention discloses a latch which assures thatonce a measuring tip is connected to the measuring wire, it staysconnected even after its address is no longer asserted on the addressbus. This aggregate permits the construction of the equivalent of alarger tip, composed of the aggregate of several small tips covering anarea as large as needed, up to the total area of all the tips together.

It is envisaged that a signal amplifier (not shown) may exist betweenthe measuring tip 110 and the switch 810 to boost the small signalcaptured by the measuring tip.

It is also envisaged that switches 810 can be doubled (not shown) foreach measuring pad 110, to select whether the pad is connected to ameasuring wire or to a ground or reference wire, which can be selectedto be near of far from the measuring tip, as needed.

Description of Our Invention—Detailed Version of Preferred Embodiment

A more detailed description of our invention is as follows. FIG. 10shows a perspective view of a basic version of our invention for aparticular main embodiment used for deep brain measurements (say, nearde subthalamic nucleus). Starting from the distal extremity (concave,hemispherical extremity in FIG. 10) of the picafina of our invention,and following now only the external features of it, there is a solid,smooth and concave part of length h_1=2.5 mm (typical value), on thesurface, inside of which there is no useful feature. Continuing on thez-dimension towards the proximal, flat extremity, next comes the partpopulated with the electrical tips, on a length h_2=25 mm. In the innerpart of it there are wires and electronics described in the sequel. Thisis followed by another smooth part on a length h_3=47.5 mm, for a totallength h_total=75 mm. These are typical values, see FIG. 10, forinsertion in the brain of a human animal; for measurements in otherparts of a human animal, or for measurements in other animals ofdifferent size, the sizes have to be adjusted as needed, withoutdetracting from the disclosure of the invention. Inside this distal parth_2 runs wires as described in the sequel. The distal end h_1 is shapedas indicated in FIG. 10 to facilitate the insertion of the picafina intothe mush brain tissue, while the proximal end (near the skull) is flatto facilitate the electrical connections and mechanical sealing. Otheraffixing features, as tapped holes for screws at the flat proximal endand equivalent features are not shown for simplicity. At the picafina'sproximal end there are a number of wire endings with the necessary meansfor connection to extension wires. In this main embodiment there is onlyone measurement wire 211 (voltage measurements), one power wire 210 (tobring power to the electronics inside the picafina), one ground (return)wire 212 and a plurality of address wires 200 (8 in this mainembodiment). As known to the practitioners of the art of electronicsmore than one return wire may be used to avoid ground loops.

The picafina's outer surface is made of some material compatible withhuman tissues, e.g. polyurethane (for the bulk) and titanium (for themeasuring metallic tips) in the main embodiment. These materials areonly used as examples used in current art picafinas, many othermaterials being possible, and the particular material being irrelevantfor our invention. The body has to be of a material that does notconduct electricity, while the tips or measuring pads are made of amaterial that is a good electrical conductor, e.g., a metal. The tipsare to serve as contact points of electrical currents somewhere in thebody, which, for the main embodiment is deep inside the brain.

The dimensions indicated in FIG. 10 were chosen for simplicity ofdescription, particularly the number of measuring tips, which is chosenlow to make the analysis simpler and the features visible in thedrawing. In this main embodiment described here there are 192 measuringtips, numbered not sequentially but accordingly to the rings they belongas 110_01_01, 110_01_02, 110_01_03 etc, until 110_01_12, for the 12 mostdistal tips (i.e., on the most distal ring of tips), then 110_02_01,etc. for the next ring, etc. until the most proximal ring of tips, whichis numbered 110_16_01, etc., in FIG. 10. In the main embodiment thesetips are made of titanium. These tips are to be the initiation points toelectrical contacts with nearby cells—neurons in this case. With theindicated dimensions, typical tip diameter is 0.654 millimeters andedge-to-edge separation is also 0.654 millimeters along thecircumference, so center-to-center separation between the tips is 1.309millimeters along any circumference at a fixed distance from any of theends (fixed z dimension). On a 5 mm. diameter picafina, there are 12such tips on a circle, only the 6 on the visible side being seen on FIG.10, at any particular distance from any of the ends, there existingother 6 tips on the back, invisible side. Along the z coordinate theseparation between pads is also 1.309 mm (typical dimension), making 16such circles populated with 12 tips each, making a total of 192 tips ona z dimension length approximately equal to 20 mm (h_2). These arepossible dimensions, in no way to be taken as restricting our invention,as many other values being compatible with our invention, as known tothe ones skilled in the art. The number of tips displayed in the drawingwas chosen to be only 12 on any circumference so as to make the drawingclearer, a typical picafina having 10 to 100 or more times moremeasuring tips on any of the rings in h_2 in FIG. 10.

Referring again to FIG. 10, describing now the inner structure of thepicafina 100, also starting from the distal end of it (the concaveextremity), the first 2.5 mm of it (h_1, typical dimensions) have nofeatures inside. In the particular preferred embodiment, said distal endis solid and made of the same compatible material as the externalsurface of the picafina. Moving towards the proximal end of thepicafina, at the distance h_1=2.5 mm. from said distal end (see FIG.10), there is at the surface a first set of electrical contacts or tips,110_01_yy (yy running from 01 to 12), along an imaginary ring on itsouter surface. These electrical tips are connected to electricalcircuits inside de picafina, which are described below. FIG. 7 a is aconceptual drawing of a cross section of the picafina of our invention,made perpendicular to the long, or z dimension shown in FIG. 10, made ata distance approximately 2.5 millimeters from the distal end, that is,at the plane containing the ring of electrical tips closest to thepicafina's distal end. What is shown in FIG. 7 a is not a drawing of thetransistors and other electronics devices as they are seen in amicroscope, but a symbolic representation of the electronics at thatposition, the actual transistor construction being out of the scope ofthe invention, not included in the invention, and part of the old art ofsemiconductor and printed circuit board manufacture. The transistorsthemselves do not even have to be in a single plane, but are stacked asneeded for connections among them. While FIG. 7 a depicts a schematic(simplified) view of the electronics circuits that determine ourinvention, FIG. 7 b shows in more detail the electronics for one singleelectrical tip, one of the 12 repeated circuits around the circle atFIG. 7 a. Each tip is connected by a similar electronics circuit to thesignal carrying wires, though varying in the address, as each tip hasits own dedicated address. These two figures best display the innovationover prior art brought by our invention, as they show the method whichallow the use of much larger number of electrical tips than prior art,and the reader is requested to pay special attention to these and itsdescription. FIGS. 7 a and 8 a only show the general features of thecircuits and their interconnections, while the details of the circuitsare shown at FIGS. 7 b and 8 b. Referring to FIGS. 7 a and 7 b, each ofthe address decoders 830_xx_yy contains a unique address written in it.Moreover decoders 830 are such that their outputs are high when theaddress at address bus 200tip is equal to the particular, unique addresswritten in said particular decoder 830, which is the tip address, andlow otherwise. Therefore, when address for tip 110_01_01 is asserted onthe address bus 200tip, that is, when 200tip has value (0000 0001) theaddress decoder 830_01_01 recognizes the address and makes its output togo high, while none of the other address decoders recognizes the addressas theirs, so all other address decoders keep their outputs low. This inturn causes the electronic switch 810_01_01 to be turned on, connectingtip 110_01_01 to the measurement wire and to the measuring instrument.Writing a different address on address bus 200, for example, (0000 0100digital=04 hex=04 decimal), causes another address decoder to selectanother tip for measurement. In the main embodiment, 8 address lines cancreate 2 power 8=256 different addresses, enough for the 196 tips in it,so 8 address lines are enough.

It is envisaged that the main embodiment may also have a latch (notshown) for each output of the decoders 830. With such latch it ispossible to have more than one tip 110 connected to the measuring wireat the same time, in effect creating an average or integratedmeasurement among several tips. Among other possibilities is to connecta large number of adjoining tips to create an effective larger area tip,thereby increasing the signal strength.

FIG. 7 b shows the electrical connections between the main conceptualblocks disclosed in the main embodiment of our invention. FIG. 7 a showsa cross section of the picafina of our invention taken perpendicular toits longer, or z-dimension, and FIG. 7 b shows these connectionsisolated from the body 100. Is shows the address decoders 830, theelectronic switches 810, the measuring tips 110, the wiring for them,the address bus and the power and the measurement wires. The twinelectronic switch 810 for selection of the ground or return wire is notshown, for simplicity. Any measuring tip may act as either signal orreturn/reference tip. Return tips may be omitted, in which case thereference may be taken as the full cell assembly, of animal body.

FIGS. 9 a and 9 b shows possible implementations of address decoder 830with inverters and AND gates. FIG. 9 a shows a decoder for addresses0001B=01D=01H and FIG. 9 b shows a decoder for address 1100B=12D=0CH(binary, decimal and hex representations). Each measuring tip has aparticular combination of inverters that determines its particularaddress. These circuits are made using the standard techniques ofsemiconductor fabrication. This is only an exemplary version, many otherpossibilities existing for address decoders, which is a mature field indigital electronics, not part of our invention. In the preferredembodiment of our invention said address decoder is also grown on thesubstrate of each layer that serves a particular set of tips 110_xx_yyat a fixed distance from the ends of the picafina, for example, the 12tips described above, part of the most distal “ring” of tips.

Returning to FIG. 7 a it shows the electronic circuits existing at thatcross section, not necessarily at their exact position, as thepositioning of the electronic parts is not part of our invention, butonly their function and logical connection. The detailed implementationof the electrical connections are known in the art of electronics. Inparticular the actual transistors and electrical connecting wires mostlikely will in practice be not on a single plane but on differentlayers, according to the established art of transistor and printedcircuit board manufacture. Rather, FIGS. 7 a and 7 b and its details areintended to show the logical connections among the devices, which willbe implemented according to the established art of die and printedcircuit manufacture, the actual implementation of the circuits beingpart of the established art. Both transistor and printed circuit boardsare mature fields on which our invention makes no improvements. Ourinvention works with this electronics that are described in this layeror some of its electronics equivalents.

For the main embodiment described, which has 16 “rings” of tips, each ata different z-coordinate and with 12 tips each, there are 16 group ofcircuits similar to the circuit described above for the most distal“ring”, except for the addresses, which is unique for each tip.

Between each plane of electronics there are vertical “wires”, which inthis case are made using the established techniques of semiconductormanufacture or of printed board manufacture, or a combination of these,such “wires” connecting all the 8 address lines 200, the “wire” 210 thatcarries the electrical power to the electronics, the “wire” 211 thatconnects the selected tip to the external measuring instrument and the“wire” 212 for ground and possibly an extra wire for latching and forseparate ground or return (not shown in FIG. 7). Such vertical wiresconnecting in parallel all 16 planar set of circuits described abovecontinue beyond the most proximal layer of measuring tips 110_16_yy tothe proximal end of the picafina, where they end at the connectors forwires 200, 210, etc. shown at FIGS. 10 and 4 b.

Said wires running inside the picafina of our invention are, in thepreferred embodiment here described, constructed with some combinationof semiconductor manufacture, printed circuit technology and manualsoldering. For example, all the address decoders 830 and the switches810 that serve a particular set of tips at a fixed axial distance fromthe ends of the picafina (say tips 110_01_01 through 110_01_12) could bemade of current technology of semiconductor manufacture, and theirconnection to each of the tips could be individually made by atechnician at fabrication, while some of the vertical connections fromlayer to layer could be made with vias and the existing technology ofprinted circuit manufacturing, while others vertical connections withthe technology of semiconductor manufacture. But printed circuittechnology, or semiconductor manufacture, or manual soldering are notintended to be restrictive for our invention, any other equivalenttechnology or any combination of them being acceptable.

From the connectors shown at the proximal end of the picafina at FIGS.10 and 4 b, wires of the necessary length (not shown) connect theproximal end of the picafina to the electrical power supply, the controland measuring instruments. The control and measuring instruments can beas simple as manual switches to set addresses and ordinary voltmetersthat need a human to read the value, to sophisticated computercontrolled instrumentation (see FIG. 11).

It is envisaged that a an amplifier may exist between the measuring tip110 and the switch 810 to amplify the weak signal captured at themeasuring tip.

Operation of Invention—Preferred Embodiment

Similarly to the description of the invention we start with a disclosureof the operation written for electrical engineers and in a succinctform, followed by a detailed explanation of the operation.

Operation of Our Invention—Short, Electrical Engineering Version

In a main embodiment, one of a large number of measuring tips isselected for connection to a single measuring wire connecting to themeasuring instrument (e.g., a voltmeter), with an address bus. Anaddress bus with n lines can select up to 2 power n individual measuringtips. The researcher or neurosurgeon inserts the picafina describedabove in the general area where he/she wants to make measurements, thenselects which measuring tip to use asserting the appropriate address inthe address lines. Once a particular measuring tip is selected, all themeasurements indicate the voltage at that particular location. Themeasuring tip can be changed later, as needed. More than one tip can beselected concurrently making use of latches that keeps a tip selectedeven after its address is changed, and an extra deselect line is capableof turning off all switches at once.

Operation of Our Invention—Detailed Version

The invention is a method and a means to make a very large number ofmeasuring tips, each usually being of smaller physical size whencompared with prior art, to make precisely located electricalmeasurements on neural and muscle tissues. The measuring tips smallersize and closer proximity to each other, when compared with previousart, is part of our invention. The researcher or theneurologist/neurosurgeon need only to insert the picafina of ourinvention on the general vicinity of the area of interest, which is initself an improvement over prior art, which required more precisepositioning of the electrode tips than our invention does. Once thepicafina is positioned in such a way that the area covered by theelectrode tips (h_2 in FIG. 10) is in the general position on whichmeasurements are to be made, the precise measuring point is chosenselecting one out of the many tips covering the target region and more.This is made with the address lines 830. For the main embodiment of ourinvention, address lines 830 are used to close the connection of one andonly one electrode measuring tip to the wire that is connected to themeasuring instrument. This is done as follows:

The address lines 830 are in such a number as to be able to createunique addresses for all the electrode tips on the particular picafina.For the main embodiment here described, with a small number of measuringtips for simplicity, 196 electrode tips, there is a need of 8 wires(making 8 bits), which can make up to 2 power 8=256 different addresses.In the main embodiment, the address is externally chosen with a set of 8DPDT switches, each switch connected at the proximal end of the picafinato one of the eight address lines 830, with which each of the 8 addresslines can be made either high or low as desired, therefore creating eachof the 196 necessary addresses. Such a manual selection is only one ofthe possibilities, it being appreciated by the practitioners of the artthat automatic selection can be made, e.g., using a programmablecomputer or similar means. The addresses are created with the ordinarybinary number system, as known to the practitioners of the art ofdigital electronics. If an address is put on 830 that does notcorrespond to any actual measuring tip, then no tip is connected andnothing happens. Once a particular address is created with said switches(for example, 0000-1010B=0AH=10D), if said address corresponds to one ofthe existing addresses of the many address decoders 830, (decoder830_10_01 for example) the address on bus 830 will be recognized by itscorresponding address decoder 830_10_01, which will respond changing itsoutput from low to high, which in turn will change the electronic switch810_10_01 that is associated with it to the “on” state, connecting themeasuring tip associated with that particular address decoder to themeasuring wire. From this time on the measuring instruments will bemeasuring the voltage at the vicinity of measuring tip which correspondsto address 10D, indicated at FIG. 10.

The measuring wire is connected at the picafina's proximal extremity toa measuring instrument, which in the main embodiment is a voltmeter withscales capable to measure millivolts and microvolts.

The selection of measuring tip can be made from a computer program,which typically has a “feeling” similar to the standard graphicinterfaces, as, for example, shown in FIG. 11 which, nevertheless, wasdrawn for the more complex embodiment described below. Such a programmay be called a DPU (Doctor's Programming Unit), for example.

DESCRIPTION AND OPERATION OF ALTERNATIVE EMBODIMENTS Second Embodimentof Our Invention. Description of the Invention Description of SecondEmbodiment—Short, Electrical Engineering Version

A second embodiment discloses the use of multiple signal wires to carrythe signal from the picafina surface to an external measuringinstrumentation (e.g., a voltmeter) and a separate second digitaladdressing system to select which of said wires is connected to theselected measuring tips. The electrical connections for this secondembodiment are shown in FIG. 8 a and FIG. 8 b. Said second digitaladdressing system is separate from the first digital addressing systemonly logically, as each is a set of wires running in parallel. Each ofthe available wires to carry the signal can be connected to any of theavailable measuring tips, allowing several simultaneous measurementsfrom different measuring tips, as many as there are signal wires. Inthis embodiment, at the same time that a measuring tip is selected, theoutput of its address decoder 830 besides closing (turning on) theelectronic switch 810 associated with the tip that corresponds toitself, also performs two functions. Firstly it enables a demultiplexeror second address decoder 831, that selects one of the signal carryingwires to connect the selected measuring tip to one of the availablesignal connecting wires—the signal connecting wire selected by saidsecond address bus (see FIGS. 8 a and 8 b). Secondly it sets the systemto latch the selected switches, so that this particular combination ofmeasuring tip+signal carrying wire will stay connected even after theaddress bus changes to select another combination. These latches are notshown in the figures as they are internal part of the switches. Also, asis typical with latches, they can be released (going to off state). Inthis case a common wire carry an unlatch signal to all latches in thepicafina of our invention (not shown). It is intended that the number ofconnecting wires is much smaller than the number of measuring tips. Oncethe addresses for a particular measuring tip and for a connecting wireare selected, these addresses are stored in local memory (latched),freeing both address buses to assert other addresses. Alternativelyaddress decoder 831 together with switch 811 can be seen as ademultiplexer.

Description of Second Embodiment—Detailed Version

The second embodiment of our invention uses two address buses, 200 forthe measuring tips, 201 to select one of a plurality of connectingwires. This alternative embodiment offers the possibility of havingseveral separate wires connecting several different measuring tips toexternal recorders working in parallel. Any measuring tip can beconnected to any of the signal measuring wires. In this embodiment thenumber of measuring tips is still very large, say a few thousands, witha smaller number of connecting wires, say a dozen to a few hundreds. Inthis embodiment, concomitantly to selecting a particular measuring tipwith decoder 830, say 110_10_01, the user sets another address inanother independent address bus 201, which is decoded by another addressdecoder 831 (FIGS. 8 a and 8 b), which selects a particular connectingwire to carry the signal captured by tip 110_10_01 to the proximal endof the picafina and from there to the voltmeter or other measuringinstrument. In this embodiment there is a latch associated with bothelectronic switches 810 and the implied internal switch in 831 becauseboth the measuring tip and the connecting wire have to stay selectedeven after the address buses 200 and 201 have other address values forother combinations.

Consequently this second embodiment of our invention extends the use ofthe addressing system to the selection of one connecting signal wirefrom a plurality of wires available throughout the body of the picafina,each one capable of connecting any of the measuring tips with theproximal end of the picafina of our invention, from which they can beextended by ordinary means to the measuring instrumentation, e.g.,voltmeters. FIGS. 8 a and 8 b shows the electronic connections andparts. Measuring tip 110 is connected via a first digitally controlledswitch 810, which turns on/off under the control of a first addressdecoder 830, to a second digitally controlled switches 811 which isturned on/off by a second digital address decoder 831, to one of thesignal connecting wires that runs inside the picafina to the proximalend of said picafina, from which connection is made as required to areading instrument, as a voltmeter. Once either address bus selects anaddress for either the measuring tip 110_xx_yy or for the signal wire211_zz the selection is latched and stay latched until a signal is sendto another wire, not shown, which has the appropriate circuitry tounlatch all the latched addresses, which can be used to select newmeasuring tips and new connecting wires with a new selection cycle. Thecombination address decoder 831 and switch 811 can be seen as ademultiplexer.

Second Embodiment of Our Invention. Operation of the Second Embodiment

To operate the second embodiment the user must start resetting all thelatches to the off state, which the user does with the latch off signal(not shown). He/she then starts selecting the first address for themeasuring tip he/she needs in the same way as is done with the mainembodiment, e.g., with individually set switches, or with a decodingpad, or with a microcomputer or any equivalent way as known to thepractitioners of the art to assert the required addresses at theappropriate address buses, then, at the same time (concomitantly) theuser also selects the address for one of the available connecting wires211_zz which run inside the length of the picafina of our invention. Inthe particular electronic design shown for the second embodiment bothaddresses have to be selected concomitantly because in this secondembodiment the address bus that selects a particular surface measuringpad also enables the address decoder that selects which signal carryingwire is chosen, so that the signal connecting wire is connected only tothe selected measuring pad, but alternative designs are possible, inwhich the selection is made not at the same time, still implementing thesame principles, this being only one possibility for implementation.Address decoder 830 being selected for that particular measuring pad,the latches are on for its electrical measuring pathway, so thecombination will latch and will stay closed after the address bus ischanged to select another combination measuring tip+signal measuringwire. With this, the user has completed the connection from the selectedmeasuring tip to a single, identifiable wire at the proximal end of thepicafina of our invention. The user selects then a second measuring tip110 and a second connecting wire 211 in the same manner as the previousone, then a third and so on, until he/she selected all the desiredmeasuring points using one of the available connecting wire for eachmeasuring tip. As described elsewhere, it is also possible to connectsaid second measuring tip 110 to the same connecting wire 211, or anynumber of measuring tips, wherein the effect is to create a virtualmeasuring tip with a larger area, which increases the current or thestrength of the signal captured. When all the measuring tip selectionsare made and the connecting wires 211 have been connected to theexternal measuring instruments the user is ready to acquire data.Several voltage measurements can be taken in parallel with this secondembodiment, for example, to study firing correlation between neurons.

A Doctor's Programming Unit (DPU) may be used to make these selections,as shown in FIG. 11 for a simplified case of fewer measuring tips andfewer signal carrying wires as a typical picafina is supposed to have.

Another alternative embodiment is the addition of a buffer amplifierbetween the measuring tip and the electronic switch 810 (not shown). Oneof the advantages of such buffer amplifier is to obviate the knowproblems of building an electronic switch 810 with no voltage dropacross itself, which is particularly important when the signals to bemeasured by measuring tips 110 are very small. Such a first endamplifier could be critical to measure the small voltages propagatingalong the neurons, captured by measuring tips 110.

Still another alternative embodiment is to have a summing amplifier (notshown) between the measuring tip 110 and the electronic switch 810. Suchsumming amplifier should receive at a first input the voltages at themeasuring tip 110, and at a second input a fixed DC constant voltageV_bias that may derive from either an external or internal source. Insuch an embodiment the electronic switch 810 receives its input at ahigh enough electric potential not to pose constraints on its design dueto voltage drop across said switch 810.

Still another alternative embodiment is to bias the input of theelectronic switch 810 (not shown), which must then be blocked frominserting current on the neurons being measured by an isolationcapacitor 115 (not shown) between said DC and the measuring tip 110.

Still another alternative embodiment of our invention (not shown infigures) is the use of radio signals to create the addresses for theaddress decoders (and/or the addresses for the signal wires on the firstalternative embodiment). In this embodiment there is no physical addresswires connecting the distal end of the picafina with the user(researcher or neurologist). Any radio communication link is feasible,over the EM spectrum, including, e.g., microwaves etc., and suchaction-at-a-distance information is sometimes referred to as telemetry.This invention does not include a new radio communication system, butsimply use existing telemetry devices. In this alternative embodimentthe connecting wires for the address bus 200 and 201 are substituted bya telemetry unit inside the picafina of our invention, which receivesthe addresses sent by the user using a transmitting unit. Once received,the addresses are stored in memory physically located at the distal endof the picafina, near the measuring tips, said storing memory taking theplace of the connecting wires. Such an alternative embodiment decreasesthe number of wires connecting the picafina with the outside world,which may be important when taking measurements on small animals, as ina mouse or even on an insect, when it may be advantageous to use smallerwires connecting the animal to the controlling and measuringinstruments.

Still another alternative embodiment of our invention is a batteryoperated device (not shown in figures) which have the advantage over themain embodiment for chronical implants (long-term implants), which aredevices that are expected to stay on for several months or even years.In this case it may be better to have the ability to have a batteryoperated, self-contained electrode system that is capable to receiveorders by telemetry link and also send results out to an externalreceiver also by telemetry link. This alternative embodiment obviatesthe need to have the animal continuously attached to a wire,particularly because it is difficult to prevent the animal fromscratching the point of penetration of the wire, with subsequentdestruction of the connection and perhaps starting an infectiousprocess. In this variation, though the implanted device is no longerphysically accessible after the surgery, its electrical properties canbe adjusted and changed via radio or magnetic or other type ofaction-at-a-distance communication. For example, the telemetry link maybe an ordinary electromagnetic link between the picafina of ourinvention and a programming unit that transmits information to thepicafina. This telemetry link may work in the same technologicalprinciples as a cell phone, or a cordless telephone, or a wirelesscomputer mouse or a wireless computer keyboard, or a remote control usedfor TV, CD, DVD or similar household devices. Some of these use infrared communication, which has limited range in implanted devices becauseof infra red radiation absorption in tissues, others use FM or otherelectromagnetic “radio” waves, which have more transmission throughbodies than infra red radiation does, and the ones that use “radio”waves use a variety of frequencies, each one with its own advantages.Depending on the size of the animal and implant depth one or other ofthese will be more advantageous over the others. The particular type oftelemetry, and the electronics to implement it as well, are notdescribed here because telemetry and electronics are old arts. In thisalternative implementation after surgical implant and after thenecessary period of healing, the electrode tip addresses are selected bytransmitting the information by telemetry (radio, etc.) to the implantedunit, which subsequently sends the information out by radio telemetryalso.

Still another alternative embodiment of our invention is to have theoutput of the address decoder latched, that is, it continues forever inthe high state when it is selected until a deselect signal is asserted.Many addresses can be chosen at the same time.

CONCLUSION, RAMIFICATIONS, AND SCOPE OF INVENTION

Thus the reader will see that the electrode measuring tips of theinvention provide a highly reliable device which offers the advantageover prior art of being able to make electrical measurements on moreprecisely located points on the vicinity of nerves and other cellsinside living organisms. The smaller dimensions of the measuringelectrodes (tips) of our invention allow for more precise measurementsfrom a single neuron, instead of average measurements from severalneurons that happen to be near a larger measuring tips or probes ofprior art. At the same time, our invention permits the measurements fromseveral tips in parallel, which tips can be adjoining to each other,making the equivalent of a larger tip of prior art. These options givemore flexibility and options to the user of our invention. Also priorart used measuring tips at the end of a dedicated physical support whichboth forced a larger than necessary physical distance between thesemeasuring points, which in turn caused the absence of measuring pointswhere potentially needed (between two tips), as well as increased traumato the organism, as each tip was the origin of a penetrating sharpobject at the end of which it sat. Moreover, the electrode measuringtips of our invention allows for changing measurement position frompoints separated by a few micrometers, or the distance between each tip,without moving the supporting structure (the picafina). This possibilityof changing the measuring tip to be used while keeping the picafina ofour invention in the same place is important, as each repositioninginvolves trauma to the animal. Moreover, the change from one tip to theother is also important, because the distance between the tips can bemade very small, a few micrometers with modern technology ofsemiconductor and printed circuit board (PCB) manufacture, which is muchsmaller than the separation between tips in multi tip measuring devicesin current use. Therefore the picafina need not be positioned withaccuracy with respect to any neuron or other body cell, and thepossibility of adjustments of the measuring position switching from onetip to another nearby tip is equivalent to micropositioning themeasurement site, or to make small changes on the measurement site.

The wires at the proximal end of the picafina of our invention do nothave to be grouped as indicated in the main embodiment, any othergrouping being acceptable, as the grouping does not alter the working ofour invention. For example, all the wires could end on a single harness,or each wire could have its own dedicated connector, or any combinationof these, because the particular form of connecting the wires are notpart of this invention.

The wires or cables at the proximal end of the picafina of our inventionmay be duplicated (redundant wires), as shown at FIG. 12, so that thepicafina of our invention can still be used if one of the wires happensto break, simply changing to its backup wire or cable.

The measuring tips can be of any shape different of the circular shapeindicated in the main embodiment without altering the scope of theinvention. For example, the measuring pads can be square shaped, asindicated in FIG. 2, or they can be elongated, as shown at FIG. 3, orthey can be in the shapes shown at FIGS. 5 a and 5 b. These variationsand many others are possible and fit particular applications, none ofthem expressing any intrinsic variation from our invention.

The very body of the picafina of our invention can have shapes otherthan cylindrical. FIGS. 6 a and 6 b show two such possible variations.Variations on the shape of the picafina of our invention to adapt tospecific applications do not constitute an intrinsic variation of ourinvention and are covered by this patent. It is envisioned that a flatsurface may be useful in many cases, due to the layered structure of thebrain.

The distal interior part of the picafina described in the mainembodiment is solid and made of the same material as its surface, butthis is not necessary, it being possible to have a hollow interior, oran interior made of a different material then the exterior surface, thisdetail not affecting the working of the invention as it will be seen bythe persons familiar with the art.

The address decoders 830 that turns on/off the switches 810, therebyconnecting the measuring tips 110 can be as simple as a digital (orbinary) comparator, for example the National Instruments 54AC520 or theTexas Instruments 5962-8681801RA, or some other more complex circuit, oreven a especially designed electronic circuit, the particular nature ofthe address decoder not impacting our invention, but only that itrecognizes that the address asserted in the address bus 200 is the sameas the address assigned to the contact that it is supposed to turnon/off.

While our above description contains many specificities, these shouldnot be construed as limitations on the scope of the invention, butrather as an exemplification of one preferred embodiment thereof and afew typical variations. Many other variations are possible. For examplethe cross section of the picafina of our invention can be of many othershape, as elliptical or rectangular, some of which are shown in FIGS. 6a and 6 b. Besides elliptical and rectangular, it can be of anyirregular shape, or the cross section can even vary along the longdimension of the picafina. The measuring tips do not have to be flushwith the picafina's body, but can be either protruding out of it or berecessed onto it. The protruding tip could be made with thenanotechnology. The dimensions suggested for the main embodiment areintended for a picafina designed to make measurements deep in the brainof a human animal; these dimensions are necessarily different when theintended animal is not a Homo, but a smaller mouse or an even muchsmaller insect, or for measurements at the brain cortex, for example,which is located just below the skull, or for measurements on the spinalcord, or from other neurons or other cells on the heart, intestines, orany other organs or extremities like arms. The measuring tips can bemade of metals other than titanium, such as platinum, vanadium, iridium,silver, gold, surgical steel, stainless steel, MP35N, platinum-iridium,amalgams, alloys, and combinations, among others. and the body can bemade of other insulators other than silicone, such as polyurethane,polyethylene, polyimide, polyvinylchloride, PTFE, ETFE, ceramics,various biocompatible polymers, or combinations of these, among others.

The connections inside said picafina are made with any of thetechnologies developed for printed circuits and/or chip manufacture(integrated circuits or IC). For example, both the subtractive and theadditive processes used in printed circuit manufacture can be used toprint the connecting power and address lines. The integrated circuitsand transistors shown as a block diagram, for example, at FIG. 7 couldbe made with the ordinary technology used for chip manufacture, as wellas some of the wires that interconnect them and/or wires that connectthem with the main connecting wires along the picafina. It is alsopossible to use a combination of these, some connections using theprinted circuit technology, other using the smaller IC technology, theparticular choice depending on the size and complexity of the particularpicafina.

Accordingly, the scope of the invention should be determined not by theembodiment(s) illustrated, but by the appended claims, drawings andinvention description, and their legal equivalents.

What is claimed is:
 1. A device for measuring an electrical signaloccurring in body cells of an animal, including a human animal,comprising: a picafina having a generally cylindrical device body with aproximal extremity, a distal extremity, an inner lumen and an outersurface; a plurality of measuring electrode tips on the outer surface ofthe picafina in fixed relative positions at the distal extremity; afirst plurality of wires running inside the lumen wherein the firstplurality of wires have wires comprising at least one element selectedfrom three groups comprising: a first group consisting of electric powerwires, a second group consisting of digital binary information wires,and a third group consisting of signal carrying wires; a plurality ofadditional wires outside the picafina device body, the additional wiresoutside the picafina for connecting the first plurality of wires to atleast one element of the group: a measuring and/or recording instrument,an electric energy storage, a control electronics; a plurality of firston/off switches, each of the first on/off switches associated with oneof the measuring electrode tips for selecting the associated measuringelectrode tip; a plurality of second on/off switches, each of the secondon/off switches associated with one of the wires belonging to the thirdgroup of wires running inside the lumen; wherein the measuring electrodetips are configured to measure the electrical signal values at the bodycells next to the respective electrode tips.
 2. The device of claim 1further comprising a plurality of electrical amplifiers, each electricalamplifier between each one of the measuring electrode tips and theassociated first on/off switch.
 3. The device of claim 1 furthercomprising a means for connecting in parallel a subset of the pluralityof the measuring electrode tips to one of the wires from the third groupof wires, the means capable of latching the on state of each of thefirst on/off switches, wherein the subset of the plurality of themeasuring electrode tips act together as a larger surface measuringelectrode tip.
 4. The device of claim 1 further comprising a latchingcircuit associated with each of the first on/off switches and with thesecond on/off switches, configured for keeping the selection made tostay selected for an indefinite amount of time after selection untilunlatched by an unlatching circuit.
 5. The device of claim 4 furthercomprising a means for un-latching all the first and second on/offswitches.
 6. The device of claim 1 further comprising: an addressingmeans having bits to form a first address to uniquely identify each ofthe measuring electrode tips and to form a second address to uniquelyidentify each of the wires from the third group of wires; a plurality offirst address decoders, wherein each of the first address decoders isfor one of the measuring electrode tips and associated first on/offswitch and each of the first address decoders having a unique digitaladdress; a plurality of second address decoders, wherein each of thesecond address decoders is for one of the wires from the third group ofwires and associated second on/off switch and each second addressdecoder having a unique digital address; wherein the first addressasserted on the addressing means at the proximal extremity is comparedto the unique digital address of the first address decoder, such thatwhen the unique address of the first address decoder is equal to thefirst address asserted on the addressing means, the first addressdecoder causes that the associated first on/off switch to enter the “on”state to select one of the measuring electrode tips, and the secondaddress asserted on the addressing means at the proximal extremity iscompared to the unique digital address of the second address decoder,such that when the unique address of the second address decoder is equalto the second address asserted on the addressing means, the secondaddress decoder causes that the associated second on/off switch to enterthe “on” state to select one of the wires from the third group of wires,thereby completing the electrical connection between the selectedmeasuring electrode tip and the selected one of the wires from the thirdgroup of wires.
 7. The device of claim 6 wherein the addressing meansfurther comprises a plurality of addressing wires composing the secondgroup of the first plurality of wires running parallel to the signalcarrying wires inside the lumen.
 8. The device of claim 6 wherein theaddressing means further comprises a wireless telemetry circuit.
 9. Thedevice of claim 6 further comprising a variable level energy sourceconfigured to apply variable levels of electric potentials to selectedelectrodes according to their digital addresses, wherein the selectedelectrodes act as source of electrical stimulation to the cells aroundthe selected electrodes.
 10. The device of claim 1 further comprising atimer electronic circuit that controls the duration of the “on” time ofthe on/off first switches and the “on” time of the on/off secondswitches, such that once one of the plurality of switches is turned “on”it is kept in the “on” state for a pre-determined time, after which thetimer electronic circuit moves the first switches and the secondswitches to the “off” state.
 11. The device of claim 6 furthercomprising a timer electronic circuit that controls the duration of the“on” time of the on/off first switches and the “on” time of the on/offsecond switches, such that once one of the plurality of switches isturned “on” it is kept in the “on” state for a pre-determined time,after which the timer electronic circuit moves the first switches andthe second switches to the “off” state.
 12. A device for measuring anelectrical signal occurring in body cells of an animal, including ahuman animal, comprising: a picafina substantially cylindrical devicebody having a proximal extremity, a distal extremity, an inner lumen andan outer surface; a plurality of measuring electrode tips on the outersurface of the picafina in fixed relative positions at the distalextremity, each measuring electrode tips connected to a firstcontrolling electronics which includes at least one element from thegroup: on/off switches, digital address decoders, digital memory andsemiconductor digital electronics; a box housing an electric energystorage and a second control electronics; an electrical signal intensitymeasurement apparatus capable of measuring the electrical signalintensity of the electrical signal occurring in the body cells near theelectrode tips, wherein the plurality of measuring electrode tips areconnected to the electrical signal intensity measurement apparatus; afirst plurality of wires with proximal extremities and distalextremities, running inside the lumen of the picafina, wherein the firstplurality of wires have wires comprising at least one element selectedfrom three groups consisting of: a first group consisting of electricpower wires, a second group consisting of digital binary informationwires, and a third group consisting of signal carrying wires; a secondplurality of wires outside of the picafina having proximal ends anddistal ends, a third plurality of wires outside of the picafina havingproximal ends and distal ends, a fourth plurality of wires outside ofthe picafina having proximal ends and distal ends and a fifth pluralityof wires outside of the picafina having proximal ends and distal ends;wherein the distal ends of the third group of wires from the firstplurality of wires are connected to the plurality of measurementelectrodes and to the first controlling electronics, and the proximalends of the third group of wires from the first plurality of wires areconnected to the distal ends of a third plurality of wires and theproximal ends of the fifth plurality of wires; wherein the proximal endsof the third plurality of wires and the proximal ends of the fifthplurality of wires are connected to the measuring/recording apparatus,wherein the distal ends of the first group of wires part of the firstplurality of wires are connected to the first controlling electronics,and the proximal ends of the first group of wires part of the firstplurality of wires is connected to the distal ends of the secondplurality of wires, and to the distal ends of the fourth plurality ofwires, wherein the distal ends of the second group of wires part of thefirst plurality of wires are connected to the first controllingelectronics, and the proximal ends of the second group of wires part ofthe first plurality of wires is connected to the distal ends of thesecond plurality of wires, and to the distal ends of the fourthplurality of wires, wherein the proximal ends of the second plurality ofwires and the proximal ends of the fourth plurality of wires areconnected to the electric energy storage unit and to the secondcontrolling electronics, wherein the second plurality of wires isduplicated as an independent fourth plurality of wires and the thirdplurality of wires is duplicated as an independent fifth plurality ofwires, whereby the fourth plurality of wires serve as an alternateconnecting electric path between the picafina and the electric storageunit and the second controlling electronics, and the fifth plurality ofwires serve as an alternate connecting electric path between thepicafina and the signal measuring apparatus, whereby if some connectingwire breaks, the duplicate connecting wire is capable of maintaining afull electrical connection between the picafina and the electric storageunit and the second controlling electronics and the signal measuringapparatus.
 13. The picafina device of claim 12, where the generallycylindrical picafina device is implanted at a first location in saidanimal, including human animal.
 14. The device of claim 13, where thefirst location in the animal is a heart.
 15. The device of claim 13,where the first location in the animal is a brain.
 16. The device ofclaim 12, where the box housing an electric energy storage and secondcontrol electronics is implanted at a second location in said animal,including human animal.
 17. The device of claim 12, where the boxhousing the electric energy storage and the second control electronicsis external to the animal, including human animal.
 18. The device ofclaim 12, where the electrical signal intensity measuring apparatus tomeasure the signal intensity of the electrical signal occurring in thebody cells reside in the box housing the electric energy storage and thesecond control electronics.
 19. The device of claim 12, where theelectrical signal intensity measuring device to measure the signalintensity of the electrical signal occurring in the body cells residesexternally to the animal, including human animal.